Solderless electrical connectors



Jan. 1, 1963 J. c. HESELWOOD 3,07

SOLDERLESS ELECTRICAL CONNECTORS Filed April 5, 1960 2 Sheets-Sheet l INVENTOR. 'Jmes Clement ffesefiuood BY Jan. 1, 1963 J. c. HESELWOOD SOLDERLESS ELECTRICAL CONNECTORS 2 Sheets-Sheet 2 Filed April 5, 1960 INVENTOR. flbmes Clemenz f/eselwaoq BY Unite States Patent O" 3,071,750 SQLDERLESS ELECTRICAL CONNECTORS James C. Heselwood, Havertown, Pa., assignor to AMP Incorporated, Harrisburg, Pa. Filed Apr. 5, 1960, Ser. No. 20,049 3 Claims. (Cl. 339-97) One of the most difiicult tasks in the manufacture of equipment using the smaller sizes (e.g., AWG 40) of film-coated wire is the stripping and soldering of these wires.

It is an object of this invention to provide means for terminating the finer sizes of film-coated wire without stripping. A further object of the invention is to provide a means of connecting fine wires together or to other circuit elements in a quick and thorough manner having high mechanical strength and low electrical resistance.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there are shown and described illustrative embodiments of the invention; it is to be understood, however, that these embodiments are not intended to be exhaustive nor limiting of the invention but are given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

In the drawings:

FIGURE 1 is a perspective illustration of one form of a wire connector embodying the principles of this invention;

FIGURE 2 is a view similar to FIGURE 1 showing the connector in assembled form;

FIGURE 3 is a fragmentary cross-section taken along plane 3-3 of FIGURE 2;

FIGURE 4 is an end view of the device shown in FIGURE 2;

FIGURE 5 is a second embodiment of the invention of this application;

FIGURE 6 is a view of the connector shown in FIG- URES 1 and 2 as attached to a printed circuit board;

FIGURE 7 is another embodiment of the principles of this invention;

FIGURE 8 is a sectional view taken along lines 8-8 of FIGURE 7; and

FIGURE 9 illustrates another embodiment of the present invention.

As shown in FIGURE 1, the connector generally designated C includes a body portion 10 with a retaining means 12 for securing it to a panel or printed circuit board. A shank I4 extends from one end of the connection and the other portion is comprised of a sleeve 16. As shown in FIGURE 1, the body member 10 tapers from the retaining means 12 to the nose portion 18. A plurality of serrations are provided on the exterior surface of the body member 10 in the area in which the connection is to be made. A matching taper 22 is provided on the inside surface of the sleeve 16'. While the preferment illustrates serrations on the body member and a smooth inner surface on the sleeve, the relationship could be reversed.

When it is desired to connect a fine wire W into a circuit, the wire is disposed along the body member 10 to that it is longitudinally positioned with respect to the serrations 20. The sleeve 16 is inserted over the body member 10 and the wire, and driven toward the base member so that the wire is firmly held to the post in the region of serrations 20. The groove in flange 12 on the connector may be used to mount a tool so that the force Patented Jan. 1, 1963 ice of driving the sleeve 22 is not transmitted to the panel supporting the connector. The net effect is to cause the serrations 20 to penetrate the insulation on the wire (FIGURE 3) and tightly lock the wire between the body member 10 and the sleeve 16. The locking taper 22 of the sleeve and body member causes the connector to be held firmly in assembled condition with the wire W therebetween. The post 10 is usually mounted to an insulated panel or circuit board before being connected into an electrical circuit by inserting the shank 14 of the connector into a hole in the board (FIGURE 6) and upsetting the shank so that it is swaged in position.

Another embodiment of the invention (FIGURE 5) comprises a pin member 30 having a generally rectangular cross-section with serrations 32 on one surface thereof. The surface having the serrations diverges from the opposite surface thus forming a tapered member. The shell 34 has an inner surface which again has a complementary locking taper. A V-shaped notch 36 is formed in the front end of the body member 30 to accommodate one end of the line wire W. This serves to guide the wire centrally of the serrations. Also, a base member 38 and a split shank 40 permit the connector to be swaged to a board.

This connector is secured to the wire in a somewhat similar fashion to the connector shown in FIGURES 1-4. One end of the wire is disposed in the notch 36' and the wire is disposed axially along the serration 32. The sleeve 34 is driven onto the body member 30 so that the locking taper between the sleeve and the serrations secures the wire to the connector.

The embodiment shown in FIGURES 7 and 8 is somewhat similar to the embodiment shown in FIGURE 5; however, the body member 50 may be formed in the shape of an inverted U (see FIGURE 8). The upper surface of the U contains a serrated section 52. An upset tab 54 formed in the post positions the wire over the serrated portion of the post. To make a connection, a wire W is disposed along the serrated surface 52 with the tab 54 assisting in proper positioning. The sleeve 56 is then fitted onto the body member 5'6 to lock the Wire between the sleeve and the body member. Again the taper on the inside of the sleeve 56 matches the taper between the upper surface of the U-shaped member and the lower portions 58 of the post.

The embodiment shown in FIGURE 9 is similar to that shown in FIGURE 5, except that a slot 61} runs lengthwise at the base of post 68 so that the wire W may be disposed therein. The slot 60 in concert with the button 64 positions the wire centrally of the serrated edge 62 of the connector member 68. Again a sleeve 70 is properly tapered to lock the wire into the connector. FIG- URE 9 shows two such connectors mounted on the frame of an electronic device.

The radial forces exerted on the connection resulting from the matching taper cause elongation of the wire. This produces and maintains good electrical contact at each serrated section. If the Wire is coated with an insulating material (e.g., varnish or oxide), the serrations Will pierce this coating to provide a copper-to-copper interface. Furthermore, since the driving force re quired to assemble the connector is at right angles to the radial force acting on the conductor, a large increase in longitudinal pressure accomplished a relatively minor increase in radial pressure and a finely controlled penetration of the serrations. The possible application force need not be precise but rather embraces a large range. This is a considerable advantage in working with fine wire because of the low tensile strength of the wire.

I claim:

1. A device for interconnecting conductors including a first member having a flange proximate one end for supporting the first member in a printed circuit board, a post portion extending toward the other end having a tapered surface forming an area of contact for a conductor to be connected, the tapered surface including a series of stepped serrations each defined by first and second abutting surfaces, the first surface being relatively perpendicular to the longitudinal axis of the post portion and the second surface being relatively parallel to the longitudinal axis of the post portion and of an area substantially greater than the first surface; a second memher having an interior surface of a taper substantially the same as the taper of the post portion of the first member, the second member being adapted to be driven onto the post portion into an interlocking frictional fit, the interior surface of the second member acting to drive a conductor against the serrations and force the abutting surfaces thereof into the conductor.

2. A connector for terminating Wires including a body member having at least one tapered outer surface, a sleeve surrounding the body member, a tapered surface on the interior of the sleeve complementing the taper on the outer surface of the body member, serrations on one of the tapered surfaces, each serration being defined by first surface substantially perpendicular to the longitudinal axis of the body member and a second surface substantially parallel to the longitudinal axis of the body member and of an area substantially greater than the first surface, the serrations thereby forming cutting edges inclined in the direction of the taper of the sleeve and body member.

3. A connector for terminating conductors including a cylindrical post tapered along its length, a segment of the length of the post being formed by series of stepped conductor cutting edges each including contiguous surfaces parallel and perpendicular respectively to the longitudinal axis of the post and of different areas; a cylindrical sleeve having an interior surface tapered to complement the taper of the post and adapted to be driven over the post to force an conductor against the said cutting and into contact with the said surfaces.

References Cited in the file of this patent UNITED STATES PATENTS 399,465 Bainbridge Mar. 12, 1889 1,986,735 Mack Jan. 1, 1935 2,134,775 Bergan Nov. 1, 1938 2,604,508 Bergan July 22, 1952 2,677,118 Stone Apr. 27, 1954 2,816,275 Harnrnell Dec. 10, 1957 FOREIGN PATENTS 1,110,799 France Oct. 19, 1955 1,140,951 France Mar. 11, 1957 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3 O7l 75O January 1, 1963 James C, Heselwood It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

9' Column 4, line 5, strike out "cylindrical"; line l2 for anedread a same llne 12, after "cutting" insert ges Signed and sealed this 3rd day of September 1963 (SEAL) Attest:

ERNEST w. SWIDER VID L- LADD Attesting Officer Commissioner of Patents 

3. A CONNECTOR FOR TERMINATING CONDUCTORS INCLUDING A CYLINDRICAL POST TAPERED ALONG ITS LENGTH, A SEGMENT OF THE LENGTH OF THE POST BEING FORMED BY SERIES OF STEPPED CONDUCTOR CUTTING EDGES EACH INCLUDING CONTIGUOUS SURFACES PARALLEL AND PERPENDICULAR RESPECTIVELY TO THE LONGITUDINAL AXIS OF THE POST AND OF DIFFERENT AREAS; A CYLINDRICAL SLEEVE HAVING AN INTERIOR SURFACE TAPERED TO COMPLEMENT THE TAPER OF THE POST AND ADAPTED TO BE DRIVEN OVER THE POST TO FORCE AN CONDUCTOR AGAINST THE SAID CUTTING AND INTO CONTACT WITH THE SAID SURFACES. 